Renewable link cartridge fuse



May 9, 1933. W u CLARK 1,907,740

RENEWABLE LINK CARTRIDGE FUSE Filed Feb, 2l. 1930 /7 f//f/ /l/ INVENTOR.

William T. Cla/"R A TTORNE Y.

Patented May 9, 1933 PATENT OFFICE WILLIAM T. CLARK, OF MILWAUKEE,WISCONSIN RENEWABLE LINK CARTRIDGE FUSE Application filed February 21,1930.

5 nection is made.

The invention resides in an improvement in the construction andarrangement of the means employed for maintaining the ends s of thefusible link disposed within the caslo ingin an electrical contact withthe terminals of the fuse, of which latter the ferrules are a part.

The invention involves the particular arrangement of a plate pivoted oneat each l5 end of the casing and adapted to partially cover and overlapthe same and upon the outer side of which cover plate the end of thefusible link is adapted to be folded and `pressed into contact. Theinvention also ini 'volves the form and mounting of such pivoted coverplate, whereby the construction and assembly are greatly simplified andrendered more economical in production.

The invention also applies to a yielding l pressure element, arrangedinteriorly at the end of the ferrule, and which is adapted to bear uponthe bent end of the fusible link,

when the ferrule is screwed upon the casing, to maintain the link incontact with the cover plate.

The invention further involves the specific construction and arrangementof certain other parts at the end of the casing.

The foregoing and other features of the y 55 invention will now bespecifically described,

and the novelty residing therein pointed out in the appended claims.

In ,the accompanying drawing:

Figure 1 is a longitudinal central sec- 19 tional view through acartridge fuse constructed in accordance with my invention, the fusiblelink being shown in edgewise elevation.

Fig. 2 is a like view of the fuse, looking i 45 in a plane perpendicularto the plane of Serial No. 430,307.

end of one of the ferrules, partly broken out to show the conguration ofthe yielding pressure element, before referred to.

Fig. 5 is an end view of Fig. l, looking from the right, with theferrule removed, showing the pivoted cover plate with one end of thefusible link bent over and engaged therewith; and

Fig. 6 is a view similar to Fig. 5, with the cover plate in its openedposition.

In the accompanying drawing the numeral 10 indicates a. tubular casingof indurated libre or other insulating material. The ends of the casingare counterbored for the reception of liners in the form of thin metal65 sleeves 11, which have a close fit in the counterbores, and project ashort distance outwardly of the ends of the casing. The ends of thecasing 10 are reduced circumferentially for a portion of the length of'70 the casing, and circular' shoulders are pro vided at the inner endsof the reduced portions. Caps 12, the side walls of which are threadedinteriorly and exteriorly, and having a large central perforation in thebot- 75 tom or ends thereof to provide an inwardly extending overhangingflange, are threaded on to the reduced ends of the casing, the rim ofthe cap abutting the circular shoulder on the casing. The flange of thecap is axially '80 spaced from the end of the casing so as to create anannular space, the latter being defined by the end of the casing, thewall and flange of the cap, and the liner 11. A pin 13 is passedradially through the wall of the k85 cap, the reduced end of the casing,and the liner 11, to hold the parts 11 and 12 in a position of assemblyupon the end of the casing and prevent their disarrangement.

The projecting end of the liner 11 is provided at one point in itsdiameter with a radial notch, and the flange of the cap with acorresponding notch, the notches being in register when the parts areassembled and fixed in position by the pin 13. 9d

The open end of the casing is partially closed by a substantiallycircular pivoted plate 14, hinged to the end of the casing, as at 15,and having a cut out portion 16 opposite the hinge. rlhe hinge portionintegral lfm with the cover plate is embodied in a radially projectingtongue 17 having opposite lateral extensions 18. The extensions 18 enterthe confined annular' space before referred to, and form journals fort-lie rotation of the hinge. The width of the tongue 17 is slightly lessthan the width of the alignedinotches in the sleeve 11 and cap 12, so asto provide free movement of the hinge in closingvand opening the coveiplate 14. The notch in the opposite edge of the pivoted cover plate 14,has a width which will enable it to receive therein, one end of afusible link of flat sheet metal of high resistance, the bottom marginof the notch being formed as a straight edge, and extending the fullwidth of the notch. It will be observed that the axial opening in the cais enlarged, this being for the purpose of acilitating the loading ofthe casings with fusible elements of the cylindrical powder pack type,as well as the bare link type.

The tongue 17 is bent from the plane of the pivoted cover plate, so thatthe projecting journals of the end lie in a plane separated somedistance from the plane of the cover plate. This construction enables avery convenient arrangement of the operating parts to be made.

The cup-like ferrules 19 are threaded interiorly for engagement with thethreaded exterior surfaces of the caps 12 of the casing. In eachferrule, I place a yielding fessure element 20, formed as a slightlydished disc from resilient sheet metal, and provided with a plurality ofnotches in its periphery. The ielding pressure element 20 may be securein longitudinally fixed relation to the ferrule 19 by spreading themetal of the ferrule over the margin of the disc 20 at a plurality ofpoints, so that the disc 20 may be permanently retained in position inthe ferrule. The notches at the margin of the disc-like yieldingpressure element 20, permit the ready escape from the casing of thegases generated when the fuse is blown, such gases passing from thecasing through the central perforations 21 in the ferrules. The dishedportions of the discs intermediate the notches in the margin provide forthe necessary yielding pressure when the ferrules are turned up to makea contact.

The fusible link 22 shown is of a special construction invented by me,and is set forth and claimed in a companion application filed February21, 1930, Serial No. 430,309, no claim herein being made to the saidlink.

In assembling the cartridge, the fusible link 22, is passed through thetubular casing and made to project evenly at the ends thereof, and thepivoted cover plates folded against the end of the casing. Theprojecting ends of the link 22, shown in full lines in Fig. 3, are thenbent over the straight edge at the bottom of the notch 16 in the pivotedcover plate, and made to lie parallel with the surface of the saidplate, as Shown by doted lines in Fig. 3. 'llie ferrules 19 are thenscrewed on to the caps 12 of the casing, until the yielding pressurediscs 20 are in engagement with the bent ends of the fusible link. Theresulting pressure in clamping the bent ends of the fusible link betweenthe Hatsurface of the pivoted cover plates 14 and the resilient discs20, insures a thorough electrical contact, which latter is securedwithout distortion of the fusible link 22 in turning up the ferrules.

The pivoting of the plates at opposite points in the diameter, as shownin Fig. 3, is preferred, inasmuch as it enables better disposition ofthe fuse link to be made.

Having thus described my invention, what I claim and desire to secure byLetters Patent of the United States, is:

1. In a cartridge fuse of the ferrule type, an insulating casing, coverplates hinged to the ends of the casing, the pivot pin bein an integralpart of the cover plate and o set aiigularly from the plane of the coverplate, and the cover plate being provided with a straight edge overwhich a flat fusible link is adapted to be folded, and a ferrule at theend of the casing for pressing the folded end of the fuse link intocontact with the cover plate.

2. In a cartridge fuse of the ferrule type, an insulating casing, aliner disposed interiorly of the casing and projecting at the endthereof, a cap secured exteriorly of the casing and provided with aninwardly eX- tending flange constituting with the liner and the end ofthe casing a circular recess, a pivoted cover plate having journalsengaged in the said recess, the said cover plate havin a straight edgeover which a flat fusible lin is adapted to be folded, and a ferrule atthe end of the casing for pressing the folded end of the fuse link intocontact with the cover plate.

3. In a cartridge fuse of the ferrule type, an insulating casing, aliner disposed interiorly of the casing and projecting at the endthereof, a cap secured exteriorly of the casing and provided with aninwardly extending flange constituting with the liner and the end of thecasing a circular recess, the outer ends of the liner and the cap beingprovided With registering radial notches leading to the said circularrecess, a pivoted cover plate having offset journals engaged in the saidrecess and a connecting tongue adapted to be moved in the said notches,the cover plate having a straight edge over which the end of a fusiblelink :is adapted to be folded, and a ferrule at the end of the casingfor pressing the folded end of the fuse link into contact with the coverplate.

4. In a cartridge fuse of the ferrule type, an insulating casing, asleeve liner in the end of the Casing and a cap exteriorly of thecasing, and a hinged cover plate; the said cap being provided With anenlarged axial opening to facilitate insertion of the fuse elements intothe Casing, and a ferrule holding the cover plate in Closed relation tothe said opening, whereby one end of the link is clamped upon the Coverplate.

In testimony whereof I have signed my naine at Milwaukee, this 20th dayof January, 1930.

WM. T. CLARK.

